This invention relates to a robot apparatus adapted to restore its normal posture by itself from an abnormal posture such as a tumbling posture and a method of controlling the posture of such a robot apparatus.
Various robots with different mechanical features are known to date including tired automotive robots adapted to move by means of revolving tires and two-legged or four-legged self-supporting walkable robots.
A robot of this type is typically provided with a mechanical system comprising actuators having a predetermined degree of freedom, sensors arranged at respective positions to detect predetermined physical quantities and a control section having microcomputers for controlling and driving the actuators individually to make the robot move by itself and/or perform a predetermined action in a coordinated manner. Such a robot is produced by assembling components including a trunk, legs and a head to make them show predetermined mutual relationships.
Walkable robots having two or more than two legs include those typically showing a profile resembling a cat or a dog and having four legs each of which is provided with a predetermined number of joints. The joints of the legs of such a robot can be controlled by recording and reproducing positional information and velocity information according to instructions or by carrying out arithmetic operations, using a kinetic model along with positional information and velocity information.
If controlled according to instructions or on the basis of a kinetic model, the motion of a known robot is designed on the basis of certain assumptions concerning the environment of the activity of the robot that is conceivable to the designer. Therefore, in an environment where those assumptions do not hold true, the robot can be forced to take an unintended posture, which by turn damages the function and/or the structure of the robot, if partly, and eventually make it go out of order. In some cases, the robot can damage the environment.
In view of the above identified circumstances, it is therefore an object of the present invention to provide means for effectively preventing a robot from being damaged or causing an accident if operated in an abnormal posture such as a tumbling posture.
Another object of the present invention is to provide a robot apparatus that can restore its normal posture by itself from an abnormal posture such as a tumbling posture and a method of controlling the posture of a robot.
According to the present invention, there is provided a robot apparatus comprising posture detection means for detecting the posture of the apparatus main body and outputting the result of the detection, posture determination means for determining if the apparatus main body is taking a predetermined posture or not on the basis of said result of the detection and posture modification means for modifying the posture of the apparatus main body when said posture determination means determines that the apparatus main body is taking the predetermined posture.
According to the present invention, there is also provided a method of controlling the posture of a robot apparatus comprising steps of detecting the posture of the apparatus main body, determining if the apparatus main body is taking a predetermined posture or not on the basis of the result of the detection and modifying the posture of the apparatus main body when it is determined that the apparatus main body is taking the predetermined posture.